<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>填充颜色</title>
</head>
<body>
<canvas id="canvas" width="500" height="800"></canvas>
<script>
    var ctx = document.getElementById('canvas').getContext('2d');
    ctx.translate(75,75);

    for (var i=1;i<6;i++){ // Loop through rings (from inside to out)
      ctx.save();
      ctx.fillStyle = 'rgb('+(51*i)+','+(255-51*i)+',255)';

      for (var j=0;j<i*6;j++){ // draw individual dots
        ctx.rotate(Math.PI*2/(i*6));
        ctx.beginPath();
        ctx.arc(0,i*12.5,5,0,Math.PI*2,true);
        ctx.fill();
      }

      ctx.restore();
    }
</script>
</body>
</html>